fixes, improvements, tests, documentation, etc.

bin/hs:
* added --debug flag

lib/App/HostScript.pm:
* use boolean, Module::Load, FileHandle
* added the parser to $self
* renamed get_systemdict to _get_systemdict
* added sub _number_test and _number_pair_test which return if a real or an integer
* added lots of error checking to defined operators
* fixed where operator results were not type::foo objects
* added operators file, eval, load, and new
* renamed parse_token to _parse_token
* added magic for type::name to handle the Perl voodoo in _parse_token
* added sub decode to run HostScript via Perl code
* added sub _to_perl which turns HostScript objects into Perl

* added POD

lib/App/HostScript/Parser.pm:
* added POD

lib/App/HostScript/Parser/Grammar.pm:
* added POD

lib/App/HostScript/Parser/Receiver.pm:
* support type::mark in got_bare
* fixed regex in got_bare to handle numbers such as 3e2 for type::real
* added POD

lib/App/HostScript/type.pm:
* renamed sub type in package type to _type
* fix regex in type::real to handle numbers such as 3e2
* added type::module which wraps any perl scalar that is a reference
* added sub module to package type
* added POD

t/*:
* plenty of tests